Methods for generating power from miniature electrical generators and power sources

ABSTRACT

A method for generating electrical power, the method including: storing potential energy in an elastic element having one end attached to a shaft and another end attached to a structure upon rotation of the shaft relative to the structure in a first angular direction; and moving a retaining mechanism between an engaged position for retaining the shaft from rotating in a second angular direction opposite to the first angular direction and a power generating position permitting the shaft to rotate in the second angular direction; wherein when the retaining mechanism is moved to the power generating position, the stored potential energy in the elastic element is converted to kinetic energy to rotate the shaft which in turn rotates a generator operatively coupled to the shaft so as to produce electrical power.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 14/752,961 filed on Jun. 28, 2015, now U.S. Pat.No. 9,590,474 issued on Mar. 7, 2017, which claims the benefit ofearlier filed provisional application No. 62/026,003 filed on Jul. 17,2014, the entire contents of each of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates generally to miniature dynamo typeelectrical generators and corresponding power sources, and moreparticularly, to miniature electrical generators and power sources forprojectiles fired by guns, mortars and the like or hand grenades and thelike.

2. Prior Art

Chemical reserve batteries have long been used in various munitions,weapon systems and other similar applications in which electrical energyis required over relatively short periods of times. In addition, uniqueto the military is the need for munitions batteries that may be storedfor up to twenty years without maintenance. Reserve batteries arebatteries designed to be stored for years, even decades, withoutperformance degradation. Reserve batteries are stored in an inert stateand can be activated within a fraction of a second with no degradationof battery capacity or power. Typical Reserve batteries are thermalbatteries and liquid reserve batteries.

The typical liquid reserve battery is kept inert during storage bykeeping the electrolyte separate from the electrodes. The electrolyte iskept in a glass or metal ampoule inside the battery case. Prior to use,the battery is activated by breaking the ampoule and allowing theelectrolyte to flood the electrodes. The ampoule is broken eithermechanically or by the high g shock experienced from being shot from thecannon.

Thermal batteries represent a class of reserve batteries that operate athigh temperatures. Unlike liquid reserve batteries, in thermal batteriesthe electrolyte is already in the cells and therefore does not require adistribution mechanism such as spinning. The electrolyte is dry, solidand non-conductive, thereby leaving the battery in a non-operational andinert condition. These batteries incorporate pyrotechnic heat sources tomelt the electrolyte just prior to use in order to make themelectrically conductive and thereby making the battery active. Thermalbatteries have long been used in munitions and other similarapplications to provide a relatively large amount of power during arelatively short period of time, mainly during the munitions flight.Thermal batteries have high power density and can provide a large amountof power as long as the electrolyte of the thermal battery stays liquid,thereby conductive.

Reserve batteries are expensive to produce, primarily since the processof their manufacture is highly labor intensive and involve mostly manualassembly. For example, the process of manufacturing thermal batteries ishighly labor intensive and requires relatively expensive facilities.Fabrication usually involves costly batch processes, including pressingelectrodes and electrolytes into rigid wafers, and assembling batteriesby hand. The reserve batteries are encased in a hermetically-sealedmetal container that is usually cylindrical in shape. In munitions,thermal batteries may be initiated during launch via inertial orelectrical igniters, or may be initiated later during the flight viaelectrical igniters. The liquid reserve batteries are usually activatedduring launch by breaking the electrolyte ampoule.

Chemical reserve batteries, including thermal batteries and liquidreserve batteries, are generally very expensive to produce, requirespecialized manufacturing processes and equipment and quality control,and are generally required to be developed for each application at hand.

All existing and future smart and guided weapons, including gun-firedprojectiles, mortars, and small and large gravity dropped weapons,require electric energy for their operation. For many fuzing operationssuch as fuzing “safe” and “arm” (S&A) and sensory functionalities andmany other “smart” fuzing and initiation functionalities, the amount ofelectrical energy that is needed is low and may be as low as 10-50 mJ,and even less. In fact, with such electrical energy levels, low-powerelectronics could be easily powered to provide the above fuzing or thelike functionalities. The amount of power required to operate many otherelectronic components, for example those used for diagnostics and healthmonitoring purposes, or for receiving a communicated signal or the likeis also very small and can be readily achieved with electrical energy inthe above range. In all such applications, particularly for poweringelectronics for fuzing and other similar “safe” and “arm”functionalities, it is highly desirable to have low-cost and safealternatives to chemical reserve batteries. This is particularly thecase for the above applications since it is generally difficult toproduce very small, miniature, reserve batteries of any kind.

In addition, in certain munitions applications a relatively small amountof electrical energy, sometimes as low as 10-50 mJ is required beforefiring to bring up at least a portion of the onboard electronics and thelike and/or to transfer firing and other information into the munitionsmemory and the like. In such applications, electrical energy iscurrently provided either by onboard electronics or by electrical energytransferred to onboard capacitors using for example induction couplingor optical or radio frequency means before the firing. In certainapplications liquid reserve or thermal batteries inside the munitionsare initiated to provide the required electrical energy. All suchoptions makes the design and operation of the munitions complex, addsignificantly to their cost and generally require a significant amountof space onboard. The latter option also has the disadvantage of if theround is not fired within a relatively short amount of time, theinitiated reserve battery can no longer provide the required amount ofpower and the round becomes inoperative.

A need therefore exists for alternatives to chemical reserve batteriesfor low power applications such as pre-fire data transfer and holdpowering and for powering fuzing electronics and other similarfunctionalities when the required electrical energy levels are low, andfor powering industrial and commercial products such as self-poweredhealth monitoring and emergency sensor.

For munitions applications, such miniature electrical generators andpower sources, hereinafter referred to as power sources, have to have avery long shelf life of up to 20 years; be low cost; and be capable ofbeing scaled to the required power level requirements, shape and size,with minimal design and manufacturing change efforts.

A need also exist for miniature power sources for munitions applicationssuch as gun-fired munitions, mortars and grenades in which theirpotential energy storage springs (elastic elements) have no storedpotential energy and the required potential energy is stored in them asa result of launch acceleration.

A need also exists for miniature power sources for munitions and otherindustrial and commercial applications in which potential energy isstored in energy storage spring (elastic) elements of the device apriori. Hereinafter, all such mechanical potential energy storageelements (whether helical or other types of springs or elastic elementsor structural flexibility) will be referred to simply as springs. Arelease mechanism is then used to release the stored potential energyand allow it to be converted to electrical energy via a mechanical toelectrical energy conversion device such as a continuously rotating or alinear or rotary vibratory magnet and coil generator device.

A need also exists for miniature power sources that are manuallyoperated through a push button type mechanisms provided on the surfaceof munitions to generate electrical energy for their pre-fire or thelike powering or through said push button or toggle or other similartype of on-off mechanisms to generate electrical energy for poweringvarious industrial and commercial low power devices. The mechanicalenergy to electrical energy conversion elements of such power sourcesmay be based on magnet and coil generators or piezoelectric or any othersuch energy conversion devices.

An objective is to provide non-chemical miniature electrical generatorsand corresponding power sources for the aforementioned and the like lowpower applications. In these power sources, mechanical potential energycan be stored in the power source and used to generate electrical energyupon occurrence of certain events, such as firing of a projectile by agun or by the release (or ejection) of a gravity dropped weapon orthrough certain manual operation. This is in contrast to chemicalreserve batteries in which stored chemical energy is released upon acertain event (such as firing by a gun or by an electrical charge),thereby allowing the battery to provide electrical energy.

Another objective is to provide non-chemical power sources areminiaturized and are manually operated through a push button typemechanisms provided on the surface of munitions to generate electricalenergy for pre-fire or the like powering or through said push button ortoggle or other similar type of on-off mechanisms to generate electricalenergy for powering various industrial and commercial low power devices.

Here, a means of storing potential mechanical energy can be elasticdeformation, such as in various types of spring elements and/or thestructural flexibility of the structure of the system in which it isused such as the structure of a projectile or the like, and notpotential energy due to gravity. It is, however, appreciated by thoseskilled in the art that potential energy may also be stored by othermeans such as by pressurizing compressible gasses such as air. Themechanical energy may be stored a priori in the said mechanicalpotential energy storage springs or be manually input at the time ofuse. The mechanical potential energy stored in the power source storagesprings can then be released via certain mechanisms to be describedeither upon the occurrence of certain intended event(s), such as firingand/or spinning of a projectile or releasing of a gravity-dropped weaponor other events appropriate to the device employing the power source ormanually through certain mechanisms. The released potential energy canthen be used to generate electrical energy using well known methods suchas by the use of active materials based elements such as piezoelectricelements or magnet and coil type generators.

To this end, the mechanical stored potential energy is preferablytransferred to a flywheel as kinetic energy which is then used togenerate electrical energy through a continuous rotation of a rotarymagnet and coil generator to achieve high mechanical energy toelectrical energy conversion efficiency. Gearing mechanisms may also beemployed to increase speed of generator rotation to further increase thepower source energy conversion efficiency.

Alternatively, the mechanical stored potential energy is used to causevibration of a mass-spring system. The vibration energy is thentransformed into electrical energy by one of the aforementionedpiezoelectric, coil and magnet or the like elements.

A second object is to provide methods and mechanisms for releasing thestored potential energy in the power sources with a priori storedmechanical potential energy. Such mechanisms include various handoperated mechanisms or various external event initiated mechanisms.Examples of such event initiated mechanisms include those operated dueto gun firing acceleration; deceleration of gun-fired projectile (theso-called set-forward acceleration); the process and/or mechanism ofreleasing (e.g., gravity dropping) the weapon from its mounting rack orthe like; pulling out or ejection of a releasing element (e.g., areleasing pin or wire); actuation or breaking of a stop element or thelike via detonation of small charges; etc.

For the power sources employing piezoelectric elements for convertingmechanical energy of vibration to electrical energy, methods describedfor mass-spring systems used in the piezoelectric based power generatorsdescribed in the U.S. Pat. Nos. 7,231,874 and 7,312,557 can generally beused in the construction of the disclosed power sources, particularlyfor those mechanical reserve power sources to be used in gun-firedprojectiles and mortars which are subject to very high-G firingacceleration levels.

In addition, in such mechanical reserve power sources, the piezoelectricelements (stacks) employed to convert mechanical energy of vibration toelectrical energy may also be used as sensors to measure setback andset-forward acceleration levels, target impact impulse levels anddirection, the time of such events and more as described in the U.S.Pat. No. 8,701,599 or 8,266,963 or 8,205,555 or 8,191,475 or 7,762,192or 7,762,191.

SUMMARY OF THE INVENTION

Accordingly, a method for the development of miniature electricalgenerators and corresponding power sources is provided. In these powersources, mechanical potential energy is stored a priori or duringactivation phase such as by pushing of a button or actuating of aswitching mechanism in elastic elements such as springs. The storedpotential energy is then released manually or upon occurrence of certainevent via certain mechanisms, such as gun firing of a projectile orgravity dropping of a weapon or throwing of a hand grenade or throughactuation of certain mechanism for example manually or via detonation ofa small charge or the like. The released energy can then be transformedinto kinetic energy of a flywheel or the like to rotate a magnet andcoil rotary generator or to vibration energy of a mass-spring system,which is then harvested by mechanical to electrical energy conversionelements such as piezoelectric elements or magnet and coil elements.

Accordingly, methods and apparatus for storing potential energy in thepower sources, and methods and apparatus for releasing the storedpotential energy manually or upon the occurrence of several events areprovided. The mechanical potential energy may be stored a priori orgenerated during the power source activation phase.

The event upon which the stored mechanical potential energy of thedisclosed mechanical power sources is released and the start ofelectrical power generation can be used to provide “safe” and “arm”(S&A) or other similar safety functionality, particularly when the powersource is used for powering fuzing means. The generated electricalenergy may also be used to power electronic circuitry and/or logics usedto provide additional “safe” and “arm” (S&A) functionality for fuzing orother similar applications. Accordingly, methods and apparatus for the“safe” and “arm” (S&A) or other safety functionality with and withoutelectronics circuitry and/or logics are also provided.

When using mass-spring type vibrating elements in the power-source, thedevice mass-spring elements may be configured to be excited also by thevibration and rotary oscillations of the munitions during the flight,thereby allowing the power source to generate additional electricalenergy. The power source may also be provided with the means to generatevibration of its mass-spring element during the flight due toaerodynamics forces, e.g., by the means to generate flutter.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the apparatus andmethods of the present invention will become better understood withregard to the following description, appended claims, and accompanyingdrawings where:

FIG. 1 illustrates a schematic of one embodiment of the miniaturereserve power source with preloaded potential energy storage element andmanual electrical energy generation initiation.

FIG. 2 illustrates an example of addition of a “safety pin” to theminiature reserve power source of FIG. 1 to prevent its accidentalinitiation.

FIG. 3 illustrates another example of the addition of a “safety pin” tothe miniature reserve power source of FIG. 1 to prevent its accidentalinitiation.

FIG. 4 illustrates another example of the addition of a “safety pin” tothe miniature reserve power source of FIG. 1 which is removable bydetonation of a small charge to initiate electrical energy generation.

FIG. 5 illustrates a schematic of another embodiment of the miniaturepower source with manually operated handle actuation which first storespotential energy in the device torsion spring element and then releasesa locking element to initiate electrical energy generation.

FIG. 6 illustrates the cross-sectional view A-A of the power sourceembodiment of FIG. 5 showing the potential energy storage and energygeneration initiation mechanism of the device.

FIG. 7 illustrates a schematic of a “push button” type embodiment of theminiature power source which generates electrical energy each time thedevice “button” is depressed.

FIG. 8 illustrates the cross-sectional view B-B of the power sourceembodiment of FIG. 7 showing the device “button” and the provided guidein the power source body.

FIG. 9 illustrates a schematic of an alternative “push button” typeembodiment of the miniature power source which generates electricalenergy each time the device “button” is depressed.

FIG. 10 illustrates the cross-sectional view C-C of the power sourceembodiment of FIG. 9 showing the “push button” shaft and itsanti-rotation key and guide.

FIG. 11 illustrates a schematic of another alternative “push button”type embodiment of the miniature power source which generates electricalenergy each time the device “button” is depressed.

FIG. 12 illustrates the block diagram of a typical electrical powersystem and the electrical energy consuming or storage system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Although this invention is applicable to numerous and various types ofdevices, it has been found particularly useful in the environment ofgenerating power onboard munitions such as gun-fired munitions, mortarand grenades. Therefore, without limiting the applicability of theinvention to generating power onboard such munitions, the invention willbe described in such environment. However, those skilled in the art willappreciate that the present methods and devices can also be used ingenerating power in other devices, including commercial and industrialsensors and other low power electronic devices for direct poweringand/or for charging appropriate electrical energy storage devices suchas rechargeable batteries or capacitors.

The basic design and operation of the first embodiment 10 of themechanical reserve power source of the present invention is shown in theschematic of FIG. 1. The mechanical reserve power source 10 isconsidered to be mounted in a structure 11 of the power source. Themechanical reserve power source 10 consists of a shaft 12, which is freeto rotate in the bearing 13 mounted in the device structure 11. Theshaft 12 is also provided with the end piece 14 to which it is rigidlyattached and which can be an integral part of the shaft 12. A torsion(such as a power type) spring 15 is also attached on one end to thestructure 11 of the power source 10 and on the other end 41 to the shaft12 as shown in FIG. 1. As can be seen in FIG. 1, a shaft 16 is providedthat engages the end piece 14 of the shaft 12 via a one-way clutch 17.The shaft 16 is attached to the input of a magnet and coil dynamo 18,which is also attached to the structure 11 of the power source 10. Aflywheel 19 can also be provided on the shaft 16 as shown in FIG. 1 toprovide for a smooth operation of the power source 10. The end piece 14is provided with a recess 20 which may be engaged by the tip 21 of thelink 22 as shown in FIG. 1. The link 22 is in turn attached to the link23 via the pin joint 24. The link 23 is in turn attached to the powersource structure 11 by the pin joint 25.

The power source 10 is originally assembled as follows. Before engagingthe tip 21 of the link 22 in the recess 20 of the end piece 14, theshaft 12 of the power source is rotated—in this case in the clockwisedirection as observed from the top—to preload the torsion power springto a desired level. The tip 21 of the link 22 is then engaged with therecess 20 of the end piece 14, thereby locking the end piece 14 to thestructure 11 of the power source and preventing it to unwind the torsionpower spring 15. As a result, mechanical potential energy is stored inthe torsion power spring 15. The assembled power source 10 is now readyfor use in the intended device.

The reserve power source embodiment 10 is designed to be manuallyinitiated. To this end, the user would at the desired time rotate thelink 23 in the counterclockwise direction as shown by the arrow 26, forexample, by applying a force to the link 23 in the direction of thearrow 27, thereby causing the tip 21 of the link 22 to exit the recess20 in the end piece 14. As a result, the end piece 14 is now free to berotated by the preloaded torsion power spring 15. The one-way clutch 17is directed such that the resulting clockwise (as viewed from the top)rotation of the end piece 14 would transmit the torsion power springtorque to the shaft 16. As a result, the potential energy stored in thetorsion power spring 15 is transferred mostly to the flywheel 19 and theshaft 16 and the rotor of the generator 18 as kinetic energy, while themagnet and coil generator 18 would begin to transform the transferredkinetic energy to electrical energy to power the intended devices. Oncethe potential energy stored in the torsion power spring 15 istransferred to the assembly of the shaft 16, flywheel 19 and thegenerator 18, the one-way clutch 17 allows the shaft 16 to continue torotate with respect to the end piece 14. The kinetic energy transferredto the assembly of shaft 16, flywheel 19 and rotor of the generator 18will then keep on being transformed into electrical energy until thekinetic energy is exhausted and the assembly would come to a stop. Ingeneral, for the sake of maximizing the mechanical to electrical energyconversion efficiency, the generated electrical energy is desired to beused as generated or stored in an electrical energy storage device, suchas a capacitor or a rechargeable battery.

It will be appreciated by those skilled in the art that once the endpiece 14 is released by the aforementioned actuation of the release link23, the links 22 and 23 are desired to be prevented from interferingwith the operation of the moving components of the reserve power source10. To this end, stops 28 and 30 may be provided to limit the motion ofthe link 23. A preloaded tensile spring 29 that connects the links 22and 23 as shown in FIG. 1 may also be provided to pull the link 22towards the link 23 upon disengagement with the end piece 14 and awayfrom interfering with the motion of the other components of the powersource 10. A preloaded compressive spring 31 can also be provided tobias the link 23 towards the stop 30 to prevent its accidental actuationand initiation of power generation as previously described.

Another feature that may be readily added to the reserve power sourceembodiment 10 of FIG. 1 is the means of proving a “safety pin” whichwould lock the initiating link 23 to the structure 11 of the powersource. The “safety pin” can, for example, be readily included at one ofthe stops 28 or 30, as shown in the close up view of FIG. 2 in whichthis region of the reserve power source 10 of FIG. 1 is drawn with theadded “safety pin” feature. In this added feature shown in FIG. 2, thelink 23 is provided with an extension 33, which is provided with a hole35. A matching extension 32 is also provided on the structure 11 of thereserve power source 10 and is also provided with a hole 34, which inthe configuration shown in FIGS. 1 and 2, i.e., before the previouslydescribed initiation of the power source 10 to generate electricalenergy, lines up with the hole 35. A “safety pin” 36 can then be passedthrough the two holes 34 and 35 to lock the link 23 to the structure 11of the reserve power source 10. The “safety pin” 36 can be provided witha finger hole end 37 for the user to readily pull out the pin 36 andallow the user to force the link 23 to release the end piece 14 and aswas previously described to initiate the power source 10 to generateelectrical energy.

In the above description of the reserve power source embodiment 10, apreloaded compressive spring 31 is indicated to be used to bias the link23 towards the stop 30 to prevent its accidental actuation andinitiation of power generation. It will be, however, appreciated bythose skilled in the art that the use of the aforementioned “safety pin”36 eliminates the need for the preloaded compressive spring 31 for thispurpose. The preloaded compressive spring 31 may still be desirable sothat between the time of “safety pin” removal and the intended reservepower source initiation, the link 23 is not accidentally actuated toinitiate the electrical energy generation.

In an alternative design, the spring 31, FIGS. 1 and 2, may be apreloaded tensile spring. As a result, as the “safety pin” 36 is pulledout as previously described, then the preloaded tensile spring 31 wouldpull on the link 23 and thereby release the end piece 14 as waspreviously described and initiate electrical energy generation process.

In reserve power source embodiment 10 of FIGS. 1 and 2, a mechanismconsisting of links 22 and 23 is shown to be used to lock the end piece14 to prevent the potential energy stored in the preloaded torsion powerspring 15 from being released and initiate electrical energy generation.It is however appreciated by those skilled in the art that numerousother similarly functioning and manually operated mechanisms may also beused to perform the same function. Such mechanisms would only need toprovide the means of pulling a locking pin, wedge, ball, etc., fromengagement with the end piece 14 and thereby allowing the preloadedtorsion power spring to freely rotate the end piece. As an example, ascan be seen in the schematic of FIG. 3, the tip 38 of the “safety pin”39 (36 in FIG. 2) itself may be used directly to lock the end piece 14to the structure 11 of the reserve power source by being inserted in therecess 20 of the end piece. Then as the user pulls out (or back) the“safety pin” 39, such as via the finger hole end 40, the end piece 14 isreleased and the reserve power source 10 begins to generate electricalenergy. As another example, a button (not shown) may be provided on thestructure 11 of the reserve power source 10, which when pushed wouldapply a force in the direction of the arrow 27 to rotate the link 23 inthe direction of the arrow 26, thereby causing the end piece 14 to bereleased and the reserve power source to begin to generate electricalenergy as was previously described.

It will be appreciated by those skilled in the art that the any one ofthe above designs of the reserve power source 10 illustrated in FIGS.1-3, and particularly the design with a “safety pin” 36, FIG. 2, with apreloaded compressive spring 31 is highly suitable for use in munitionssuch as hand grenades that are equipped with electronic and relateddevices that require electrical energy to operate. In such anapplication, the user must first pull out the “safety pin” 36, and thenpress the link (lever) 23 to initiate electrical energy generation.

In the reserve power source embodiment 10, with the “safety pin” shownin the schematic of FIG. 3, the “safety pin” 39 is designed to bemanually removed by the user to initiate electrical energy generation.Alternatively, the means of pulling “safety pins” of different type, forexample those similar to the ones in FIG. 1 or FIG. 2 or others withlocking wedge elements, locking balls, etc., may be removed (pulled backor rotated away or the like) via detonation of a small charge. Anexample of such a “safety pin” removal mechanism actuated by thedetonation of a small gas generating charge is shown in the schematic ofFIG. 4. Here the mechanism is constructed as a cylinder 42 which isattached to the housing 11 of the reserve power source 10. The cylinder42 houses a piston 43 to which a piston rod 44 is attached. In theconfiguration shown in FIG. 4, the tip 47 of the piston rod 44 is shownto be in engagement with the recess 20 on the end piece 14, therebylocking it to the structure 11 of the reserve power source 10. Thecylinder is also provided with an electrically initiated gas generatingcharge 45, with the initiation wires 46. Upon initiation of the gasgenerating charge 45, gas pressure builds up in the cylinder 42 on theside of the gas generating charge 45, thereby forcing the piston 43 tomove away from the end piece 14, thereby causing the tip 47 of thepiston rod 44 to disengage the end piece, thereby allowing the reservepower source to begin to generate electrical energy.

In the “safety arm” release mechanism of FIG. 4, an electricallyinitiated gas generating charge is shown to be used. It is, however,appreciated by those skilled in the art that an inertially initiated gasgenerating charge may also be employed. Such inertially initiateddevices are well known in the art (see e.g., U.S. Pat. Nos. 7,587,979;7,587,980; 7,437,995; 8,042,469, 8,061,271; 7,832,335; 8,418,617;8,651,022 and 8,550,001), and for munitions applications they could bedesigned to initiate due to the firing setback acceleration or firingset forward acceleration or due to target impact shock loading or firingspin acceleration or spinning velocity induced centripetal acceleration.

Another embodiment of a power source 50 is shown in the schematic ofFIG. 5. All components of the power source 50 are identical to those ofthe embodiment 10 of FIG. 1, except for the modification to the endpiece 48 (14 in the embodiment of FIG. 1) and its release mechanism. Inaddition, the torsion power spring 15 (such as a high stiffness torsionspring—hereinafter referred to as torsion spring) is not preloaded,i.e., the power source has no stored mechanical potential energy priorto the initiation process to be described. As a result, the power source50 is no longer a “reserve” type power source.

The cross-sectional view A-A, FIG. 5, showing the indicated changes tothe end piece 48 and the basic method and mechanism of storingmechanical potential energy in the torsion spring 15 and its release isshown in FIG. 6.

As can be seen in the cross-sectional view A-A of FIG. 6, the end piece48 (14 in the embodiment of FIG. 1) is provided with a similar recess 52(20 in the embodiment of FIG. 1) and is also provided with an actuatinglever 54. A locking element 49 is also provided that can slide back andforth in the sliding bearing 51 provided in the structure 11 of thepower source 50. In the configuration shown in FIGS. 5 and 6, the tip 53of the locking element 49 is in engagement with the recess 52 of the endpiece 48, thereby locking it to the structure 11 of the power source andpreventing the end piece and the shaft 12 from rotating. In addition, inthe configuration shown in FIGS. 5 and 6, the torsion spring 15 is notpreloaded and the power source would have zero stored mechanicalpotential energy to convert to electrical energy. The latter feature ishighly desirable in devices where safety is of great importance such asin various types of munitions, such as hand grenades.

In operation, the user rotates the lever 54 and thereby the end piece 48in the clockwise direction as shown by the arrow 61, for example byapplying a force in the direction of the arrow 62 to the lever 54 asshown in FIG. 6. The resulting counterclockwise rotation of the shaft12, FIG. 6, causes the torsion spring 15, FIG. 5, to be loaded andmechanical potential energy be stored in the torsion spring. As thelever 54 is further rotated in the counterclockwise direction andincreasing amount of mechanical potential energy is stored in thetorsion spring 15. The lever 54 is provided with an extension element 55which is provided with a curved surface profile 58, FIGS. 5 and 6. Thelocking element 49 is also provided with an engagement top piece 56,FIGS. 5 and 6, with an inclined surface 57 as shown in FIG. 6. As can beobserved in FIG. 5, the extension element 55 is sized such that it canpass over the surface of the locking element 49 (in front of theengagement top piece 56) but its surface 58 would otherwise engage thesurface 57 of the engagement top piece 56. Then as the lever 54 isrotated in the clockwise direction, at some point, the tip 59 of theextension element 55 moves over the frontal surface of the lockingelement 49, followed by engagement of the surface 58 with the surface57. Then as the lever 54 is rotated further in the clockwise direction,the curved surface 58 will force the locking element 49 to move to theright, FIG. 6, thereby disengaging the tip 53 of the locking element 49from the recess 52 of the end piece 48. The torsion spring 15 will thenbe free to rotate the shaft 12 and thereby begin the previouslydescribed process of generating electrical energy.

It is appreciated by those skilled in the art that in the power sourceembodiment 50 of FIGS. 5 and 6, a preloaded compressive spring element63, FIG. 6 (not shown in FIG. 5 for clarity) may also be added to biasthe tip 53 of the locking element 49 into the engagement with the recess52 of the end piece 48. Such a biasing spring may be desirable in casesin which the device may be subjected to incidental shock loading orvibration or the like that may cause the power source to be accidentallyinitiated.

In the embodiments of FIGS. 1 and 5, a torsion power spring and atorsion spring were used, respectively, to store potential mechanicalenergy for generation of electrical energy. It is, however, appreciatedby those skilled in the art that in applications in which the shaft 12is rotated only a small fraction of a full turn, probably at most 90-120degrees, which is mostly the case for the power source embodiment ofFIG. 5, then other types of springs such as regular or preloaded tensileor compressive springs or their combination or almost any other type ofelastic element may also be similarly used for the purpose of storingmechanical potential energy.

Another embodiment of power source 60 is shown in the schematic of FIG.7. In this embodiment 60, a “push button” element 65 is provided thatcan slide up and down in the structure 64 of the power source. The pushbutton element 65 is provided with side elements 66, which are fixed tothe push button element 65 and can slide freely in the guides 67provided in the structure 64 of the power source, as shown in FIG. 7 andin the cross-sectional view B-B of the power source shown in FIG. 8.Stop element 70 which is fixed to the structure 64 of the power sourceis also provided to limit downward displacement of the push buttonelement 65. At least one preloaded compressive spring 71 is alsoprovided to bias the push button element upwards. At least one stop 72can also be provided to limit upward displacement of the push buttonelement 65.

In a cavity 68 provided in the push button element 65, FIG. 7, isprovided a relatively large pitch threaded portion 73, which mates witha matching threaded surface 74 on a shaft 69 as shown in FIG. 7. Theshaft 69 is also provided with a free end 76, over which is mounted aflywheel 77 via a one way clutch 78. The flywheel 77 is then connectedto the input shaft 81 of a magnet and coil type electrical energygenerator 82 via a coupling element 79 which is fixedly attached to theflywheel 77, as shown in the schematic of FIG. 7.

The internal and external threaded surface 73 and 74, respectively, aredesigned with relatively large pitch and are provided with enoughclearance so that by pressing the push button element 65 down in thedirection of the arrow 75, the shaft 69 is rotated with minimalresistance (other than inertial resistance of the flywheel, coupling 79and rotor of the generator 82; generator 82 torque and frictionalforces).

In operation, the user presses on the push button element 65 rapidly byapplying a force in the direction of the arrow 75, FIG. 7. Downwardtranslation of the push button element 65 causes the shaft 69 to rotate,transmitting the rotation through the one-way clutch 78 to the flywheel77 and through the coupling 79 to the input shaft 81 of the electricalgenerator 82. The one-way clutch is configured such that while the shaft69 is being rotated by the push button element as it moves down in thedirection of the arrow 75, the motion is transmitted to the assembly ofthe flywheel 77, and that the flywheel 77 is free to continue to rotateonce the downward translation of the push button element has ended. Theuser can press the push button element 65 down hard (apply a relativelylarge force) to transfer a relatively large amount of energy to theflywheel 77 and its assembly. The user can also press the push buttonelement 65 down until its motion is stopped by the stops 70. The userwill then allow the at least one preloaded compressive spring 71 to pushthe push button element 65 back to its uppermost position shown in theschematic of FIG. 7.

It will be appreciated by those skilled in the art that the work down bythe user by displacing the push button element 65 downwards certaindistance by applying certain amount of force is transferred to theassembly of the flywheel 77, coupling 79 and the rotor of the generator82 as kinetic energy—less the friction and other losses and the amountof electrical energy generated during the process. The kinetic energystored in the assembly is then transformed to electrical energy by thegenerator 82. In the meantime, the user can keep on pressing down on thepush button element 65 and letting it bounce back by the at least onepreloaded compressive spring 71, each time adding more kinetic energy tothe flywheel and its assembly for conversion to electrical energy.

In the schematic of FIG. 7 regular screw threads are shown to beprovided on the mating internal and external surfaces 73 and 71,respectively. It is, however, appreciated by those skilled in the artthat to increase the efficiency of the power source embodiment 60 inconverting the work done by the user to electrical energy by reducingthe friction related losses between the contacting surfaces 73 and 71,one may instead use a ball screw. Ball screws are well known in the artand are commonly used in machinery to reduce friction losses in powerscrews.

It will be appreciated by those skilled in the art that the basic designand operation of the “push button” type power source embodiment isillustrated by the schematic of FIG. 7 for the sake of clearlyidentifying each component of the power source and describing theirfunction and the operation of the overall power source. In practice,however, it is generally highly desirable to have a very compact powersource. For example, the at least one springs 71 may be designed as asingle conical spring that is assembled around the shaft 69 andcollapses as the push button element 65 is pressed down into a singlelayer. The flywheel 77 and the rotor of the generator may also befabricated as one unit in a pancake type generator design tosignificantly reduce the size of the power source for a prescribedamount of energy generation requirement. In practice, similar approachesare readily implemented on the designs of the other embodimentsdescribed previously and later in this disclosure to achievesignificantly more compact power source designs.

In the power source embodiment 60, no mechanical energy storage element(spring or other type of elastic element) is used for a priori storageof mechanical potential energy. As a result, the power source 60 is asimple power source and not a “reserve” type power source. This featureof this power source of having zero stored mechanical energy prior tothe electrical energy generation process to be described is highlydesirable in devices where safety is of great importance, such as invarious types of munitions, such as hand grenades.

An alternative design 80 of the power source embodiment 60 is shown inthe schematic of FIG. 9. This alternative embodiment 80 is also a “pushbutton” type. In this embodiment 80, a “push button” element 83 with anattached shaft 84 which can slide up and down in the bearing 85 providedin the structure 86 of the power source 80. While sliding up and down inthe bearing 85, the shaft 84 is prevented from rotation with respect tothe structure 86 of the power source by a key member 87, which isengaged with the guide 99 in the structure 86 of the power source 80, asis shown in the cross-sectional view C-C of FIG. 10. A slightlypreloaded compressive spring 88 is provided around the shaft 84 betweenthe push button element 83 and the surface 90 of the structure 86 of thepower source 80 to bias the said push button element away from thesurface 90. The shaft 84 is also provided with a stop element 89 whichlimits the biasing action of the spring 88 as shown in the schematic ofFIG. 9.

The shaft 84 is provided with a section 91, which is threaded as a highpitch screw. Mating with the threaded screw is the nut element 92, overwhich is mounted a flywheel 93, via a one-way clutch 94. A thrustbearing 94 a is provided under the nut element 92 to support the nutelement 92 against the structure 86 of the power source 80. In thisembodiment of the present invention, the flywheel 93 is fabricated withoutside gearing that engages with a pinion 95, which is mounted on ashaft 96 of a magnet and coil electrical generator 97. The use of thegearing allows the rotary speed of the electrical generator 97 to beincreased and thereby increasing the amount of electrical power that thegenerator 97 can produce.

In operation, the user presses on the push button element 83 by applyinga force in the direction of the arrow 98, FIG. 9. Downward translationof the push button element 83 and the shaft 84 causes the threadedsection 91 to rotate the nut element 92. The nut element 92 in turn willrotate the flywheel 93 through the one-way clutch 94. The flywheel 93(outer gear) will in turn rotate the pinion 95, which would directlyrotate the rotor shaft 96 of the electrical generator 97. Electricalenergy thereby begins to be generated by the electrical generator 97.The one-way clutch 94 is configured such that while the nut element 92is being rotated by the threaded section 91 of the push button shaft 84as the push button 83 is being translated down in the direction of thearrow 83, the rotation of the nut element 92 is transmitted to theflywheel 93, and the flywheel 93 is free to continue to rotate once thedownward translation of the push button element has ended.

The user can press the push button element 83 down hard (apply arelatively large force) to transfer a relatively large amount of energyto the flywheel 93. The user can also press the push button element 83down until its motion is stopped by the stops 89. The user will thenallow the preloaded compressive spring 88 to push the push buttonelement 83 back to its uppermost position shown in the schematic of FIG.9.

It will be appreciated by those skilled in the art that the work down bythe user by displacing the push button element 83 downwards a certaindistance by applying a certain amount of force is transferred to theassembly of the flywheel 93, pinion 95, the nut element 92 and the rotorof the generator 97 as kinetic energy—less the friction and other lossesand the amount of electrical energy generated during the process. Thekinetic energy stored in the assembly is then transformed to electricalenergy by the generator 97. In the meantime, the user can keep onpressing down on the push button element 83 and letting it bounce backby the spring 88, each time adding more kinetic energy to the flywheeland its assembly for conversion to electrical energy.

Yet another embodiment 100 of the power source embodiment 60 is shown inthe schematic of FIG. 11. This alternative embodiment 100 is also a“push button” type. The design and operation of this embodiment is thesame as the embodiment 80 of FIGS. 9 and 10 and is indicated with thesame numerals, except for the method and components for transferringmotion and mechanical energy from the flywheel 93 to the electricalenergy generator type employed. In the embodiment 100 of FIG. 11, acoupling element 101 is fixedly attached to the flywheel 93. Thecoupling element 101 is annular in shape to prevent interference withthe motion of the nut element 92, the one-way clutch 94 and the threadedportion 91 of the push button shaft 84. The coupling element 101 is thendirectly connected to the rotating side of the pancake type magnet andcoil electrical generator 102, which is in turn fixed to the structure86 (body) of the power source 100. The pancake type electrical generator102 type used is the one with open center to allow for the motion of thethreaded portion 91 of the push button shaft 84 and which is providedwith a thrust or other bearing that can support an axial load inreaction to the force applied to the push button element 83 to drive thepush button shaft 84 down in the direction of the arrow 98.

The operation of the “push button” power source 100 is the same as thatof the embodiments 60 and 80 of FIGS. 7 and 9, respectively. Inoperation, the user presses on the push button element 83 by applying aforce in the direction of the arrow 98, FIG. 11. Downward translation ofthe push button element 83 and the shaft 84 causes the threaded section91 to rotate the nut element 92. The nut element 92 in turn will rotatethe flywheel 93 through the one-way clutch 94. The flywheel 93 will inturn rotate the electrical generator 102 via the coupling 101.Electrical energy thereby begins to be generated by the electricalgenerator 102. The one-way clutch 94 is configured such that while thenut element 92 is being rotated by the threaded section 91 of the pushbutton shaft 84 as the push button 83 is being translated down in thedirection of the arrow 83, the rotation of the nut element 92 istransmitted to the flywheel 93, and that the flywheel 93 is free tocontinue to rotate once the downward translation of the push buttonelement has ended.

In the above power source embodiments 50, 60, 80 and 100 of FIGS. 5, 7,9 and 11, respectively, a spring (elastic) element is deformed by directrotation of a link (power source 50 of FIG. 5) or translation of anelement (power sources 60, 80 and 100) by the user. The motions would inturn deform a spring (elastic) element and store mechanical potentialenergy in the spring (elastic) element. Alternatively, a number oflinkage and/or gear mechanisms or other similar mechanical motion orforce amplifying or reducing or otherwise modifying mechanisms may beprovided to increase the performance of the power source, i.e., theamount of electrical energy and/or power that it can generate and/orreduce its size or vary its finished shape to certain available ordesirable shape.

It is appreciated by those skilled in the art that the electrical energygenerated by the above embodiments may either be used directly to powercertain electrical or electronic circuitry and/or to store in certainelectrical energy storage device, such as capacitors, super-capacitorsor rechargeable batteries. In almost all such cases the electricalenergy generated by the power sources have to be regulated by electronicand logic circuitry to provide electrical power to the intendedelectrical power consuming devices. The block diagram of the resultingtypical electrical power system is shown in FIG. 12.

In FIG. 12, the block 103 is intended to indicate one or more of thedisclosed power sources 10, 50, 60, 80 and 100 of FIGS. 1, 5, 7, 9 and11, respectively. The electrical energy generated by the power source(s)is then regulated by the electronic and logic circuitry 104 and useddirectly in the electrical energy consuming device 105 and/or used tocharge the electrical energy storage device such as a rechargeablebattery or capacitor 106. In general, a related charging circuitry 107is also required for safe charging of any electrical energy storagedevice 106.

While there has been shown and described what is considered to bepreferred embodiments of the invention, it will, of course, beunderstood that various modifications and changes in form or detailcould readily be made without departing from the spirit of theinvention. It is therefore intended that the invention be not limited tothe exact forms described and illustrated, but should be constructed tocover all modifications that may fall within the scope of the appendedclaims.

The invention claimed is:
 1. A method for generating electrical power,the method comprising: storing potential energy in an elastic elementhaving one end attached to a shaft and another end attached to astructure upon rotation of the shaft relative to the structure in afirst angular direction; and moving a retaining mechanism between anengaged position for retaining the shaft from rotating in a secondangular direction opposite to the first angular direction and a powergenerating position permitting the shaft to rotate in the second angulardirection; wherein when the retaining mechanism is moved to the powergenerating position, the stored potential energy in the elastic elementis converted to kinetic energy to rotate the shaft which in turn rotatesa generator operatively coupled to the shaft so as to produce electricalpower.
 2. The method of claim 1, further comprising preventing anunintended movement from the engaging position to the power generatingposition.
 3. The method of claim 1, further comprising preloading theelastic element to store the potential energy.
 4. A method forgenerating electrical power, the method comprising: converting atranslation of a translating member slidably disposed in a structureinto a rotation of a shaft operatively coupled to the translating memberupon an application of a force to the translating member; and engagingan input shaft of a generator with the shaft only when the shaft rotatesin a predetermined rotational direction.
 5. The method of claim 4,further comprising biasing the translating element against theapplication of the force.
 6. A method for generating electrical power,the method comprising: converting a translation of the translatingmember slidably disposed in a structure to a rotation of a rotatingmember operatively coupled to the translating member upon an applicationof a force to the translating member; engaging the input shaft of agenerator with the rotating member only when the rotating member rotatesin a predetermined rotational direction.
 7. The Method of claim 6,further comprising biasing the translating element against theapplication of the force.